1. Field of the Invention
The present invention relates to a plasma display panel in which a discharge of gas between glass substrates are utilized for displaying an image, and more particularly, to a discharge electrode in a plasma display panel.
2. Background of the Related Art
Having all the advantages of the clear picture and the variety of screen sizes of the cathode ray tubes, and of the light and thin liquid display panel, the plasma display panel is considered as the next generation display. In general, the plasma display panel is light as it weighs approx. ⅓ of the cathode ray tube of the same screen size, and thin as it has a thickness below 10 cm even for a large sized panel of 40 to 60xe2x80x3. Moreover, though the cathode ray tube or the liquid crystal display has a limitation on a size in displaying a digital data picture and a full motion picture on the same time, the plasma display panel has no such a problem. And, while the cathode ray tube is influenced from a magnetic force, the plasma display panel is not influenced from the magnetic force, permitting to provide a stable picture to the watchers. And, since the pixels are controlled in a digital fashion, with no distortion of images at corners of the screen, the plasma display panel can provide a picture quality better than the cathode ray tube. The plasma display panels, using a gaseous discharge inside of the panel in displaying an image, are used as TV receivers, monitors, indoor and outdoor signboards and the like having large sized displays, particularly, directing to displays of the HDTV(High Definition Television) age, since the plasma display panel has a simple fabrication process as provision of active element to every cell is not required, is easy to provide a large sized screen, and has a fast response speed. The plasma display panel is provided with two glass substrates sealed together having electrodes coated thereon perpendicular, and opposite to each other, and gas filled in a space between the two glass substrates. There are pixels at portions the electrodes are crossed. In operation, a voltage higher than 100 volts are provided between the perpendicular electrodes, to cause a glow discharge of the gas, for displaying an image by using a light provided in the discharge. There are a two electrode type, a triode type, and a four electrode type in the plasma display panels with respect to a number of electrodes each cell has, wherein the two electrode type has two electrodes to which addressing and sustain voltages are provided on the same time, and the triode type, called as a surface discharge type, is adapted to be switched or sustained by a voltage provided to a electrode at a side of a discharge cell.
A related art triode surface discharge type plasma display panel will be explained with reference to the attached drawings. FIG. 1 illustrates a perspective view of a disassembled upper and lower substrates of the related art plasma display panel, FIG. 2 illustrates a section of a related art plasma display panel, FIG. 3 illustrates a plan view of scan electrodes and sustain electrodes of a related art plasma display panel, FIG. 4 illustrates a section across line I-Ixe2x80x2 in FIG. 3, FIG. 5 illustrates wiring of scan electrodes and sustain electrodes of a related art plasma display panel, FIGS. 6Axcx9c6D illustrate a discharge principle of a related art plasma display panel, and FIG. 7 illustrates an electric field formed between a pair of discharge electrodes and spreading of a discharge.
Referring to FIG. 1 and 2, the related art triode surface discharge type plasma display panel has an upper substrate 10 and a lower substrate 20 bonded and sealed together to face each other. On the upper substrate 10, there are scan electrodes 16 and 16xe2x80x2 and sustain electrodes 17 and 17xe2x80x2 parallel to each other, a dielectric layer 11 coated on the scan electrodes 16 and 16xe2x80x2 and the sustain electrodes 17 and 17xe2x80x2, and a protection film 12. On the lower substrate 20, there are address electrodes 22, a dielectric film 21 on an entire surface of the substrate including the address electrodes 22, partition walls 23 on the dielectric film 21 between the address electrodes 22, and a fluorescent material 24 on surfaces of the partition wall 23 and the dielectric film 21 in each discharge cell. The upper substrate 10 and the lower substrate 20 are bonded together by frit glass, and a space between the upper and lower substrates 10 and 20 is filled with a mixture of inert gas, such as helium He and xenon Xe, to a pressure in a range of 400xcx9c500 Torr, to form a discharge space. In general, the inert gas filled in the discharge space of a D.C. plasma display panel is a mixture of helium and xenon (Hexe2x80x94Xe), and the inert gas filled in the discharge space of an A.C. plasma display panel is a mixture of neon and xenon (Nexe2x80x94Xe).
Referring to FIGS. 3 and 4, of the scan electrodes 16 and 16xe2x80x2 and the sustain electrodes 17 and 17xe2x80x2, the electrodes 16 and 17 are formed of transparent material, and the electrodes 16xe2x80x2 and 17xe2x80x2 are formed of a metal for enhancing light transmission of each discharge cell. The metal scan electrode and sustain electrode 16xe2x80x2 and 17xe2x80x2 are provided with a discharge voltage from a driving IC fitted outside of the panel, and the transparent scan electrode and sustain electrode 16 and 17 are provided with the discharge voltage to the metal electrodes 16xe2x80x2 and 17xe2x80x2, to cause a discharge between adjacent transparent electrodes 16 and 17. The transparent electrode 16 or 17 is formed of indium oxide or tin oxide of a total width of approx. 300 xcexcm, and the metal electrode 16xe2x80x2 or 17xe2x80x2 is a thin film consisting of three layers of chrome-copper-chrome. A width of the bus electrode 16xe2x80x2 or 17xe2x80x2 line has approx. ⅓ of a width of the transparent electrode 16 or 17 line.
FIG. 5 illustrates wiring of the scan electrodes Smxe2x88x921, Sm, Sm+1, - - - , Snxe2x88x921, Sn, Sn+1 and the sustain electrodes Cmxe2x88x921, Cm, Cm+1, - - - , Cnxe2x88x921, Cn, Cn+1 arranged on the upper substrate, wherein, while the scan electrodes are insulated from each other, all the sustain electrodes are connected in parallel. In FIG. 5, the section enclosed by the dashed line represents an effective surface an image is displayed thereon, and the other section represents a non-effective surface no image is displayed thereon. The scan electrodes on the non-effective surface are in general called dummy electrodes 26, a number of which are not particularly limited.
The operation of the aforementioned triode surface discharge type AC type plasma display panel will be explained with reference to FIGS. 6Axcx9c6D.
Referring to FIG. 6A, when a driving voltage is applied between the address electrode and the scan electrode, an opposed discharge is occurred between the address electrode and the scan electrode. The opposed discharge excites the inert gas in the discharge cell, so that a portion of the inert gas is divided to electrons, ions and excited species. As shown in FIG. 6B, a portion of the ions collides onto a surface of the protection film, which causes emission of secondary electrons from the surface of the protection film. The secondary electrons collide with the gas in a plasma state, to spread the discharge. As shown in FIG. 6C, when the opposed discharge between the address electrode and the scan electrode ends, wall charges with opposite polarities are generated on surfaces of the protection film over the sustain electrode and the scan electrode, respectively. And, as shown in FIG. 6D, when the driving voltage provided to the address electrode is cut off during the wall charges with opposite polarities build up at the scan electrode and the sustain electrode continuously, there is a surface discharge occurred in a discharge region on a surface of the dielectric layer and the protection layer due to a potential difference between the scan electrode and the sustain electrode. These opposed discharge and the surface discharge cause electrons in the discharge cell to collide onto the inert gas in the discharge cell, to generate an UV ray of 147 nm wavelength in the discharge cell as the inert gas is excited. The UV ray collide onto the fluorescent material coated on the address electrode and the partition wall, to excite the fluorescent material, which generates a visible light, that permits to form a picture on the screen.
However, the related art plasma display panel has the following problems.
As described, it can be known that a sustain discharge between one pair of the sustain electrodes in each cell sustains light emission of an initially lighted cell. Therefore, it is required to increase a width of the transparent electrode 16 or 17 to increase an amount of discharge between the electrodes for enhancing luminance in lighting the cell, which, however, increases a discharge capacitance in proportion to an increase of a transparent electrode area, that drops a luminous efficiency and increases a power consumption. And, even if the transparent electrode has a comparatively high transmittivity, since the transparent electrode has certain extent of transmission reduction factor, to drop the transmittivity relative to the increase of the width of the transparent electrode, the luminance drops, on the contrary.
Accordingly, the present invention is directed to a plasma display panel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a plasma display panel which can minimize an increase of power consumption and drop of transmittivity while a width of a transparent electrode is increased for increasing an amount of discharge.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the plasma display panel includes a plurality of pairs of sustain electrodes on one of two bonded substrates, each having a transparent electrode and a metal electrode for sustaining an initial discharge between the electrodes for a preset time period, wherein the transparent electrode has a plurality of pass through holes.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.